An Epidemiology/Biostatistics Core is proposed to oversee all data collection activities at Akwesasne, to provide outreach tot he mohawk community, to serve as a resource to the individual research projects of the Program, and to build upon our previous work regarding PCB exposures, body burdens, and health effects among Native Americans residing near a Superfund hazardous waste site. Working with the Mohawk community and relying upon nearly 10 years of experience at Akwesasne, this Core Unit will enroll study participants from 400 Mohawk families over a five year period. Adults over the age of 35 years will be emphasized, given their greater likelihood of exposure. All adult participants will be administered a core interview to assess dietary, residential, and occupational exposures, together with relevant background variables. The Epidemiology/Biostatistics Core also will coordinate data collection for two human health research projects. In addition, it will serve as a liaison with the Laboratory Services Core, with responsibility for indoor air, dust and tap water monitoring for PCBs and blood sampling for 68 PCB congeners, p,p'-DDE, mirex, hexachlorobenzene, thyroxine, triiodothyronine, thyrotropin, testosterone, and beta-estradiol from all study participants. This Core Unit will assess in vivo cytochrome P-4501 A2 activity in selected Mohawk adults through a caffeine breath test, a safe and non- invasive procedure that measures the rate at which labelled carbon dioxide is exhaled as an indirect monitor. Outreach will consist of transmitting the results to study participants, assisting the Mohawk community in developing health education and promoting programs, and evaluating mortality, morbidity, and risk factors patterns at Akwesasne using vital records, cancer registry reports, hospital discharge data, laboratory analyses and the core interview. The Epidemiology/Biostatistics Core will provide technical expertise to the human health projects and will furnish all students and projects in the program with statistical support. Using its familiarity with exposure assessment, Geographic Information Systems, epidemiologic and statistical methods, and public health, this Core unit will assess the exposure status of adult mohawk participants to PCBs for all relevant sources, and determine the relationship of exposure to body burdens, cytochrome p-450 activity, and alteractions in endocrine hormones. Economy of effort will be achieved by having these functions performed by one central unit. This coordinated approach was recommended by the Mohawk community, and has been endorsed by our Expert Advisory Panel to minimize duplication and disruption.